1. Field of the Invention
The present invention relates to a recording apparatus. A recording apparatus particularly suitable to apply the present invention is of a type having an ink jet head.
2. Related Background Art
In the past, recording systems which can record an image on a recording medium (referred to as "recording sheet" or merely "sheet" hereinafter) such as a paper or an OHP sheet have been proposed to include a recording head of various types. Such recording heads are of wire dot type, heat-sensitive type, heat-transfer type or ink jet type.
Among these recording systems, particularly, the ink jet recording system is of the type that the ink is directly ejected or discharged onto the recording sheet and is being considered as a recording system having the advantages that the running cost thereof is inexpensive and the operation thereof is noiseless.
Further, in the recent ink jet recording system, particularly, the recording head thereof has been manufactured by the film forming technique or micro-working technique in the semi-conductor device, and thus, has been realized as more compact and cheaper one. Consequently, for example, a disposable or non-returnable recording head having an integral ink tank has also been proposed, so that the recording system itself becomes compact and simple.
On the other hand, the ink jet recording system having the above-mentioned various advantages has been widely used as recording means of various apparatuses such as an electronic typewriter, word processor, facsimile, copying machine and the like. In this case, the ink jet recording system has the construction corresponding to the function and usage inherent to such apparatus.
Further, the electronic typewriter, word processor and the like have a tendency to be small-sized, light-weight and portable; in this respect, it is required that the ink jet recording system used with these apparatuses be compact and simple.
The above-mentioned tendency regarding the recent ink jet recording system, i.e., the compactness and simplification require toward simplification of the elements themselves constituting the ink jet recording system and the simplification of the mechanisms connecting these elements.
Among these elements and mechanisms, a mechanism for feeding the recording sheet requires a relatively large space for installation thereof in the recording system, and, accordingly, by simplifying this mechanism, the effective compactness and simplification of the system can be anticipated. Particularly, in this feeding mechanism, a biasing means pressed against means for feeding the recording sheet such as conveying rollers, ejector rollers and the like, for providing a conveying force (friction force) between such feeding means and the recording sheet is a main part of the feeding mechanism. The biasing means is embodied as a pressure roller and a paper hold-down plate urging the conveying roller, or a spur urging the ejector roller.
On the other hand, the recording sheet feeding mechanism in the electronic typewriter must have the construction corresponding to various recording sheets such as a plain paper, envelopes and the like, in particular, the construction corresponding to the thickness of the recording sheet.
Above all, the paper hold-down plate has not only a function for causing the conveying roller to generate the conveying force, but also a function for regulating the feeding direction of the conveying roller to properly maintain a distance between the recording head and the recording sheet. Thus, in order to demonstrate such functions effectively, the paper hold-down plate and associated mechanisms, and the material forming these elements must correspond to the recording sheet.
Further, when the relatively thicker recording sheet such as the envelope is conveyed, there arises a problem that the discrepancy between, for example, the conveying roller and the pressure roller occurs during the conveyance of the recording sheet, thus causing the positional discrepancy in the recording position on the recording sheet.